Obviously, a high quality DVD player might have a better picture quality, for the same connection type (for example, component/YUV), than a crappy player. But it's more about which connection type the player and TV have. Composite on a good player and TV would probably be worse than component on a crappy player and TV.
DVDs are natively YUV/YCbCr, so the best connection for them is component. Blu-ray's are full R/G/B (HDMI).
Only OLED TVs are on par with CRTs, in terms of black levels, and color accuracy. Most OLEDS are 4K these days, so you would preferably need a 4K blu-ray player, or some other 4K source, to go with them. I don't know how good OLEDs are at upscaling. Ideally, you wouldn't need to upscale- the result is never going to be perfect.
"The distinction between the past, present and future is only a stubbornly persistent illusion." -Albert Einstein